How do you transfer a picture to dark fabric?

The most effective way to transfer a picture onto dark fabric is by using carbon or transfer paper.

Transferring Pictures with Carbon or Transfer Paper

This method is favored for its ease and effectiveness, especially on dark materials. Here's how to do it:

Place the Carbon/Transfer Paper: Lay the carbon paper or transfer paper onto the dark fabric with the waxy side (carbon) or coated side (transfer) facing down.
Position Your Pattern: Secure your picture or pattern on top of the carbon or transfer paper.
Trace the Design: Using a pen, stylus, or tracing wheel, firmly trace over the lines of your pattern. The pressure transfers the image onto the fabric below.
Check the Transfer: Carefully lift the pattern and carbon/transfer paper to see if the design has transferred clearly. If necessary, go over areas again with the tracing tool for a more pronounced result.

Type of Paper: Carbon paper leaves lines that may be more difficult to erase than those from transfer paper.
Tracing Pressure: Make sure you apply sufficient pressure when tracing to ensure the image transfers properly, without pressing so hard that you damage the fabric.
Test: It's a good idea to test the transfer on a scrap piece of fabric to ensure you are happy with the result before transferring to your main piece.

This method, as noted by the reference, is the easiest and a preferred option for transferring images onto dark fabrics.